import java.util.Scanner;
public class test12 {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        double money=sc.nextDouble();
        if(money>=5000){
            System.out.printf("%.1f",money*0.6);
        }else if(money>=2000) {
            System.out.printf("%.1f",money*0.7);
        }else if(money>=500) {
            System.out.printf("%.1f",money*0.8);
        }else if(money>=100) {
            System.out.printf("%.1f",money*0.9);
        }else if(money>=0) {
            System.out.printf("%.1f",money);
        }
    }
}

